diff options
| -rw-r--r-- | README | 45 |
1 files changed, 16 insertions, 29 deletions
@@ -1,36 +1,33 @@ -minitramfs is a minimal initramfs generator. I use this on my desktop Gentoo -system. For my laptop Arch system, I use mkinitcpio. - -Basically, it's a suckless initramfs generator: it does exactly what I need. -You need something else? Patch it, it's only 117 lines. Or use mkinitcpio or -dracut, I won't feel bad. +minitramfs is a minimal initramfs generator, in the "suckless" style: it does +exactly what I need. You need something else? Patch it, it's only 80 lines. Or +use mkinitcpio or dracut, I won't feel bad. Features: - uses existing system tools -- password LUKS unlock +- LUKS password unlock - SSH remote unlock -- firmware loading (trivial, done by kernel) -- extremely fast initramfs creation: compression off: ~70ms cold cache, ~30ms +- firmware loading +- extremely fast initramfs creation: compression off: ~80ms cold cache, ~30ms warm; lz4 --best: 1.6s - udev/mdev-free module loading - no temporary files during creation -- extremely fast initramfs runtime: ~zero overhead compared to direct kernel - loading -- minimal code: 117 SLOC total (init + make + Makefile + unlock) +- minimal runtime overhead +- minimal code: 80 SLOC total (init + make + Makefile + unlock) - pure POSIX shell + POSIX Makefile Drawbacks: - uses existing system tools +- requires exact module list - pure POSIX shell + POSIX Makefile Usage: 0. Read (skim) https://wiki.gentoo.org/wiki/Custom_Initramfs. -1. Install busybox, dropbear, e2fsprogs if you use ext4, and C toolchain for - building gen_init_cpio. +1. Install busybox, dropbear, e2fsprogs for e2fsck, and C toolchain for + gen_init_cpio. 2. Adjust ./init as required: a) Adjust networking as required. For example, use static IP instead of DHCP, or @@ -41,24 +38,14 @@ Usage: c) Change or remove fsck for non-ext4 roots d) Put whatever you want: usr mount, NFS root, whatever. -3. Adjust ./make as required: - a) Put your needed commands in gen_cpio_list. - b) Select your desired compressor at the end. Try make comp_bench for a comparison. - summary: lz4 is usually best, xz if storage is important above all (saves - a few MB but adds ~0.5s to boot), gzip is mediocre on both size and - speed, lzo is usually worse than gzip, never use bzip2 or lzma. - -4. Customize cpio_list.txt with your required files. Remember that commands - must go in ./make (for library detection), and device files except - /dev/console and non-empty directories can be omitted. +3. Adjust ./make as required. Mainly, put your needed commands in gen_cpio_list. -5. Add your public keys to authorized_keys. Note that dropbear only supports - RSA and ECDSA keys. +4. Customize cpio_list.txt with your required non-executable files. -6. make +5. Add your public keys to authorized_keys. -7. sudo make install +6. make && sudo make install -8. Configure your boot loader/boot manager to use initramfs.img. +8. Configure your boot loader/manager to use initramfs.img. 9. Use as usual. For remote unlock, SSH to port 2222 and "exec unlock". |